The demand for radiation curable coatings, adhesives and inks has rapidly increased in recent years. In general, oligomers account for more than 50% of the formulated curable raw materials by reason of their superior compatibility with many solvents and adjuvants commonly employed in coating formulations and their ease of application to substrates. Of the oligomers, acrylates which undergo radical initiated polymerization are most commonly used. However, since radical initiated processes are known to be inhibited by the presence of oxygen, care must be taken to provide an oxygen-free environment, e.g. with a blanket of nitrogen, during curing which adds to the expense of the operation. Also, it has been found that acrylate cured coatings lack the degree of adhesion and mechanical properties required in many commercial applications.
Certain epoxides have been used in some degree as oligomers for irradiation curing; however, the curing rates of these chemicals, which is exceedingly slow, has limited their use.
Accordingly, it is an object of this invention to provide a radiation curable coating material which overcomes the difficulties enumerated above.
Another object of this invention is to provide a polyfunctional resin as a coating material which is highly resistant to chemical attack, has good adhesion to substrates such as metal and glass surfaces and which are resistant to mechanical abrasion.
Another object is to provide a commercially feasible and economical process for the preparation of the present coating materials.
These and other objects of the invention will become apparent from the following description and disclosure.